Add option --dump-render-tree to content_shell to dump the render tree as text.

content/shell/shell.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/shell/shell.h"
 
+#include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/path_service.h"
 #include "base/string_util.h"
+#include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/tab_contents/navigation_controller_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/shell/shell_messages.h"
+#include "content/shell/shell_switches.h"
 #include "ui/gfx/size.h"
 
 // Content area size for newly created windows.
 static const int kTestWindowWidth = 800;
 static const int kTestWindowHeight = 600;
 
 namespace content {
 
+namespace {
+
+class ShellObserver : public WebContentsObserver {
+ public:
+  explicit ShellObserver(WebContents* web_contents);
+  virtual ~ShellObserver();
+
+ private:
+  // WebContentsObserver overrides.
+  virtual void DidFinishLoad(int64 frame_id,
+                             const GURL& validated_url,
+                             bool is_main_frame) OVERRIDE;
+  virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(ShellObserver);
+};
+
+ShellObserver::ShellObserver(WebContents* web_contents)
+    : WebContentsObserver(web_contents) {
+}
+
+ShellObserver::~ShellObserver() {
+}
+
+void ShellObserver::DidFinishLoad(int64 frame_id,

[jam, 2012/01/27 18:22:30]

nit: up to you, but if a class is declared and defined in a cc file, it's always
shorter (and IMO more readable) to inline all the methods). 

+                                  const GURL& validated_url,
+                                  bool is_main_frame) {
+  if (!is_main_frame)
+    return;
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kDumpRenderTree))
+    return;
+  RenderViewHost* render_view_host = web_contents()->GetRenderViewHost();
+  render_view_host->Send(
+      new ShellViewMsg_CaptureTextDump(render_view_host->routing_id(), false));
+}
+
+void ShellObserver::WebContentsDestroyed(WebContents* web_contents) {
+  delete this;
+}
+
+}  // namespace
+
 std::vector<Shell*> Shell::windows_;
 
 Shell::Shell()
     : window_(NULL),
       url_edit_view_(NULL)
 #if defined(OS_WIN)
       , default_edit_wnd_proc_(0)
 #endif
   {
     windows_.push_back(this);
@@ skipping 27 matching lines @@
                               const GURL& url,
                               SiteInstance* site_instance,
                               int routing_id,
                               TabContents* base_tab_contents) {
   TabContents* tab_contents = new TabContents(
       browser_context,
       site_instance,
       routing_id,
       base_tab_contents,
       NULL);
+  new ShellObserver(tab_contents);

[jam, 2012/01/27 18:22:30]

actually, do you need a new WebContentsObserver or can you just make Shell be a
WCO?

   Shell* shell = CreateShell(tab_contents);
   if (!url.is_empty())
     shell->LoadURL(url);
   return shell;
 }
 
 void Shell::LoadURL(const GURL& url) {
   tab_contents_->GetController().LoadURL(
       url,
       content::Referrer(),
@@ skipping 47 matching lines @@
 void Shell::DidNavigateMainFramePostCommit(WebContents* tab) {
   PlatformSetAddressBarURL(tab->GetURL());
 }
 
 void Shell::UpdatePreferredSize(WebContents* source,
                                 const gfx::Size& pref_size) {
   PlatformSizeTo(pref_size.width(), pref_size.height());
 }
 
 }  // namespace content